Many people say they want to exercise more but often lack the discipline to make it happen. When people first join a gym, their enthusiasm for exercise would seem to be at its peak. Would a financial incentive help them get their new membership off to a positive start? That's the question Case Western Reserve University behavioral economist Mariana Carrera explored in a recent study published by the National Bureau of Economic Research.

Carrera and her colleagues offered 836 new gym members a financial reward if they went at least nine times in a six-week period. This didn't seem too difficult to the new members, most of whom said they expected to work out three times a week. The reward? $30 to $60 in Amazon gift cards, or another prize of equivalent value. As for the result, only 57% of the incentivized group made nine or more visits. Just 48% of a control group that got the reward either way hit the nine-visit mark. In terms of average visits per week, the difference between these groups was even smaller. "People were hugely over-optimistic about how often they'd be visiting the gym," Carrera summarized. As a behavioral economist, she sees this as a case of "time inconsistency" — a struggle between what our current and future self wants. She recently discussed her findings with Crain's and their implications for employers looking to create incentives to get their workers healthier.

Why is it so hard to motivate ourselves to exercise?

Habits are really difficult. You don't need an economist to tell you that. Habits are very ingrained and changing them can be tough. We are not the first researchers to try to use financial incentives to get people to exercise with the idea that if we pay you to do something that is habit-forming, then maybe once we stop paying you, you will continue doing it because by then you will be over the hump of being sore, and you are now enjoying the benefits of exercise, for example. We designed this study with the aim of targeting people who had just enrolled in a monthly gym membership thinking that they must be at some sort of peak of internal motivation. But ultimately we were disappointed with the results because they suggested the opposite. We basically found our incentives had a very small effect on people's ability to start a habit.

Why do you think the effect was so small?

The new members thought they'd be going twice as much as they needed to go to earn the incentive, and that might have made this incentive less salient initially to them. They might not have thought that they really needed to behave differently, if in their mind they were definitely going to earn the reward.

It seemed too easy to them?

Exactly. They were overly optimistic. If we were to try a different approach, we might suggest waiting to see how people's initial routines develop and then try to target them at a time when they have realized that they are going as often as they want to go. We have also thought about how our study gave one threshold for everybody. It did push people who were close to nine visits over the hump, but it might not have been motivating for people who were far below the threshold. Some of our evidence even suggested that there might be a discouraging effect of setting this threshold for somebody who is far below it.

What do you mean by that?

Instead of just choosing a number of visits over a long period of time, maybe we should incentivize people to go once every week or spread it out so that we are really guiding them in starting a routine that they follow every week. Another approach might be to use social incentives. Things like going to group classes or appointments with a trainer can be very effective methods for some people to continue going to the gym. When other people are expecting to see you there, you're accountable.

With these findings in mind, what advice would you give a company looking to design a wellness program for its employees?

Be aware of the challenges in designing a one-size-fits-all program. A lot of companies are choosing one incentive that is threshold-based. Employers might think instead about incentivizing participation in programs that will be more guided than just a gym visit. Some people might need a little more instruction to figure out how to fit exercise into their daily life. I also think people who have never gone to the gym before might feel out of place, not know how to use the machines or feel that they stick out if they don't look like the typical muscular guy who's lifting weights over there.

So would offering Zumba after hours on the premises be a better idea?

Possibly. Anything that makes exercise easier and more accessible is a good idea. This could be bringing an exercise class to your building or doing something during the lunch break that people can participate in. I haven't seen research that quantifies those effects but I do think that anything that makes it easier or more convenient is going to increase a person's take-up.

What motivates you to exercise?

I feel better when I exercise every day, even a little bit. So I try to motivate myself to do just 15 minutes each day, because it's easier to fit it in my schedule and I know that a little bit is better than nothing.

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